ast uctu e
8: Case Studies for Neighborhood Change
To examine what kind of neighborhood change might be expected due to the redesign of the McGrath/O’Brien corridor, I chose the following examples for more in-depth case studies based on an initial survey of their similarities. McGrath is a non-waterfront highway slightly removed from the center of any major Central Business District (CBD). Many other prominent examples of highway removal/ reorientation involve downtown waterfront interstates such as Boston’s Central Artery and Portland’s Harbor Drive. I believe that the waterfront location of these highways is a signifi cant part of their redevelopment, with their location driving land values/shifts in use and investment in very different patterns from inland locations. These areas also, for example, receive additional public investment in the form of new convention centers, stadiums, or other public amenities (see New York’s Javits Center and Intrepid Sea Air and Space Museum; Boston’s Convention Center; and Portland’s new waterfront park as examples of additional investment for the renewal of downtowns and waterfronts.) Likewise, after careful consideration, I also chose to exclude San Francisco’s Embarcadero because of its waterfront, downtown aspect.128 I did, however, retain the West Side Highway in New York because of other important similarities and lessons in the case.
Central Freeway / Octavia Boulevard, San Francisco, CA
Octavia Boulevard bears a resemblance to McGrath-O’Brien case through its non-waterfront location that is slightly removed from San Francisco’s CBD. Furthermore, the site is surrounded by a mix of uses, with dense residential areas as well as small businesses.
Cyprus Freeway / Mandela Parkway, Oakland, CA
This site bears resemblance to McGrath in that it passes through lower-income/minority neighborhoods with a mix of industrial, commercial and older residential areas. It is also removed from the downtown district and does not border any waterfront. Oakland itself bears similar functionality to Somerville and East Cambridge, in that it is a city in and of itself but it also functions as an early industrial suburb of a larger city, namely San Francisco, which is now faced with redevelopment opportunities. The corridor winds through dense residential sections but also through some low-intensity, auto-dominated districts.
West Side Highway, New York, NY
The West Side Highway was one of the earliest elevated highways, built around the same time as McGrath/O’Brien’s original route. The area is similarly industrial and
128 In spite of the parallel between the MUNI investment there and the Green Line investment at McGrath.
which is shifting as development pressures increase. Its waterfront location means its context differs slightly from the Somerville case, but its examination by Context Sensitive Solutions.org makes it a valuable investigation of how CSS guidelines can be applied for a positive project outcome.
8.1: Precedent #1: Central Freeway / Octavia Boulevard, Hayes Valley, San Francisco, CA
History:
Central Freeway was a spur built in 1959129 into the Hayes Valley neighborhood of San Francisco in the midst of a freeway building spree that threatened to crisscross the city.
Even though it was just a relatively short stub, it was nonetheless blamed for negative impacts on the neighborhood. These included the usual three: neighborhood isolation;
increased congestion and air pollution; and economic decline. While residents therefore called for its removal, many others feared traffi c mayhem if it was removed.130 The argument was abruptly shifted in 1989, when the Loma Prieta earthquake damaged the highway structure. The resulting forced closure created an unexpected chance to observe traffi c patterns without this link in place. The viaduct was, however, repaired and continued operation until another closure in 1996, when a series of ballot measures were put forward to determine whether to continue repairing the structure versus remove it. In 1999, the city and Caltrans agreed to replace the structure with a boulevard, and hired Allan Jacobs and Elizabeth MacDonald (authors of The Boulevard Book) to design it. The boulevard was offi cially opened in 2005.
Octavia Corridor’s Redesign
The Central Freeway originally touched down to connect to the street grid at Fell Street and Oak Street, two major east-west routes.131 Now it instead connects to Market Street, fi ve blocks to the south. The square formerly obliterated by the ramps’
touchdown is now a green park. The new boulevard has two travel lanes in each direction and one frontage lane in each direction. MacDonald writes that:
129 John King, “An Urban Success Story: Octavia Boulevard an Asset to Post-Central Freeway Area,”
San Francisco Chronicle, 3 January 2007, B1, http://sfgate.com/cgi-bin/article.cgi?f=/c/a/2007/01/03/
BAG4VNBUJM1.DTL.
130 Congress for the New Urbanism, “San Francisco’s Octavia,” accessed February 2011, http://www.cnu.org/
highways/sfoctavia.
131 John King, “An Urban Success Story.”
Figure 23: Street view, Octavia Boulevard, San Francisco (Preservenet.com)
“…a major consideration was to keep the boulevard as narrow as possible so that there would be room for new buildings along its eastern side, replacing structures torn down when the freeway was built. Having buildings facing onto the side access roadways was crucial for these spaces to make sense, whether the buildings were residential or commercial.”132
According to its designers, Octavia Boulevard is the fi rst true multiway urban boulevard built in the United States since about the 1920s, with the exception of one in Chico, California, which was created on a railroad right-of-way in the 1950s.133
Traffi c patterns have been simplifi ed by eliminating left turns at most intersections.
Even right turns are restricted from the center lanes. The traffi c is also calmed and dispersed by a lane shift encouraging a left onto Fell Street, while through connectivity is maintained by local lanes, marked by a different pavement type, through to Hayes Street.
132 Elizabeth MacDonald, “Building a Boulevard,” Access 28, (Spring 2006): 2-9.
133 Elizabeth MacDonald, “Building a Boulevard.”
Figure 24: Context Map, Octavia Boulevard, San Francisco
Cyclists are now accommodated by sharing the local access lanes with cars. This solution cuts down on the overall width of the right-of-way and also brings a woonerf-like shared space to slow cars as well as afford cyclists more room. This solution was based on the shared lanes along the Esplanade in Chico, CA.134 Unfortunately the design of the frontage lanes has precluded right turns from center lanes and caused some confusion at intersections. This confi guration may function better if there is room for a considerable buffer / merge area (20+ feet) between lanes for a more comfortable merge, but it still results in rather awkwardly converging traffi c.
Impact
The impact of the transformation from viaduct to boulevard has been noteworthy.
In terms of the area economy, property values in the neighborhood have risen signifi cantly.
Prior to the removal of the viaduct, condominium prices in Hayes Valley were 66% of citywide averages; after the completion of the boulevard, prices are around 91% of the city average, with most of the increase occurring nearest to the project site.135
Gentrifi cation
The CNU reported that “residents noted a signifi cant change in the nature of the commercial establishments in the area,” from lower end establishments towards
“trendy restaurants and high-end boutiques.”136 In expectation of this and the threat of gentrifi cation, the city planned to construct units of affordable housing in the land opened up by the freeway. Overall, nearly 1000 new housing units will be built.137
Robert Cervero, of the Department of City and Regional Planning at the University of California at Berkeley, completed an analysis of Octavia Boulevard’s near-term impact on surrounding real estate prices.138 He also examined the Embarcadero Freeway removal’s impact on San Francisco’s waterfront. Cervero used a matched-pair statistical analysis of census tracts to compare the difference changes in tracts that were adjacent to the project versus those in a similar neighborhood that did not host such an intervention. The neighborhoods were compared through data available before and after the freeways were removed.
134 Elizabeth MacDonald, “Building a Boulevard,” 8.
135 Congress for the New Urbanism, “San Francisco’s Octavia.”
136 Congress for the New Urbanism, “San Francisco’s Octavia.”
137 Seattle Department of Transportation, “Seattle Urban Mobility Plan”, January 2008, 6C-2, http://www.seattle.
gov/transportation/docs/ump06%20SEATTLE%20Case%20studies%20in%20urban%20freeway%20removal.pdf 138 Robert Cervero, Junhee Kang and Kevin Shively, “From elevated freeways to surface boulevards:
neighborhood and housing price impacts in San Francisco,” Journal of Urbanism 2:1 (2009), doi:
10.1080/17549170902833899.
In the Hayes Valley “impact zone” around the new Boulevard, Cervero noted the following:
• 32.9% increase in total white population; 35.9% decrease in total black population, with the opposite trend noted in comparison zone.
• Decrease in percent of households with children from 37% to 23.4%
• In a hedonic analysis of real estate prices, Cervero found that they:
– Initially increased with distance from the corridor, refl ecting the negative impact of the viaduct
– After the construction of the boulevard they increased by $116,000 (2005) but this amenity effect decreased with distance from the new boulevard.
These statistics point to a strong gentrifi cation trend, real estate value boost, and
neighborhood economy shift along the Octavia corridor due to the amenity effect of the new boulevard. Fortunately, this trend was foreseen by city offi cials who proposed a strong affordable housing component of the new construction anticipated along the boulevard.
Approximately 900 units were expected to be built there; half of these are to be low-income.
Caltrans transferred ownership of land uncovered by the highway removal to the city, so that these new parcels may be developed according to local vision. In addition, parking standards in the area have been relaxed in order to keep building, owning, or renting there affordable. In 2005, the Octavia Boulevard Housing Design Competition invited designers to explore creative options for the development of the narrow lots made available by the freeway removal.139
Circulation
139 San Francisco Prize, “Octavia Boulevard Housing Design Competition – Competition Kit,” February 2003, http://www.sfprize.com/plusdoc/Part_1_Introduction_Site_Context.pdf.
Figure 25: Before and after, Octavia Boulevard, San Francisco (Google)
12’
Figure 26: Octavia Boulevard, San Francisco: Typical Section
The new route is not without congestion. At peak times, traffi c can back onto surrounding streets, particularly those on Oak Street making a southwards turn towards the Central Freeway ramp; as a result of this backup, there have reportedly been problems with non-local drivers using the non-local lanes as a through route.140 There are reports of numerous collisions because of the new lane structure and a slowdown in bus service.141 One critic commented that “the parallel lanes are awkward for drivers who want to move from the local lanes into the central path. Some of that can be helped by changing the timing on traffi c lights. But boulevards are so unfamiliar to most people, and the distance is so short -- fi ve blocks north to south -- that confusion is guaranteed.”142
At least some of the source of this problem may be that the local lanes aren’t clearly marked as such. A change in the design that widened the local lanes and did not reserve more expensive patterned/textured “local” pavements for them—thus they act and look too much like through streets, which was not the original intent of the design. Elizabeth MacDonald commented that the width and orientation of the traffi c lanes was a “major issue” because they did not conform to the traffi c engineering standards:
“Applying a standard interpretation of fi re engine access rules to the side roadways would have resulted in very wide lanes. To solve this problem, the design team proposed placing the median trees near the central roadway and giving the access roadway side of the median a mountable curb. Thus, in the event of an emergency, a fi re engine could easily enter the access road by
140John King, “An Urban Success Story.”
141 Philip Langdon, “Freeways Give Way to Boulevards-Slowly,” New Urban Network, 01 July 2008, 1, https://
newurbannetwork.com/ad/redirect/13430/t85?url=node/6928.
142 John King, “Octavia Boulevard – an Urbane Triumph: Few Flaws Found on Test Drive of City’s Newest Entry Route,” San Francisco Chronicle, 13 September 2005, http://articles.sfgate.com/2005-09-13/bay-area/17391760_1_freeway-ramp-fi rst-time-drivers-oak-street.
driving with one wheel on the median. This design approach was vetted with the fi re department and they agreed to it. In the end, lane-width compromises were reached all around, and the central lanes ended up eleven feet wide, the access lanes ten feet wide, and the parking lanes eight feet wide.”143
Nine to ten and a half feet would have been adequate for these lanes and would have kept speeds down. There were similar arguments over intersection design. Engineers argued for the standard wide turning radii and to have the local access roads rejoin the travel lanes for intersections – possible a still more confusing scheme. The designers argued for keeping the access roads separate, even with their own stop signs. This may not have worked out as expected, as it is the relationship between the local roads and the main traffi c lanes that causes much of the confusion at Octavia’s intersections. The center lanes and the side lanes function effectively as separate but parallel streets, with the center lanes confi ned to through circulation as they might be on a limited access road, since turns are constricted;
and with the side lanes having their own signage and signalization. This is a very different format from what drivers are accustomed to, but it is one that allows dual functionality of a through street on the one hand and a quiet neighborhood side street on the other.
In the end, MacDonald cites two key failures that have caused the problems with the access roads. Firstly, these lanes are still too wide and too inviting for through traffi c. The transition between the freeway and the boulevard allows too-fast traffi c through these widths. There has also been a lack of successful experimentation with the signalization of the access roads.144
Lessons
Overall, the project has been hailed as a success, winning numerous planning awards and the accolades of the local community and the city at large. In spite of being only fi ve blocks long, the boulevard has become a landmark for urban planners seeking to reduce the impact of automobiles on the urban form. The San Francisco Chronicle even wholeheartedly excused the street’s congestion level, stating that “It means the boulevard is fi lling a need.”145 Based on this survey of research on Octavia Boulevard, the case can offer several important lessons for the redesign of McGrath/O’Brien:
• Do not underestimate the ability of traffi c to reroute itself after the removal of or decrease in capacity of a key link. Octavia Boulevard replaced a roadway that at one time accommodated 90,000 ADT; it now contains about 45,000 ADT.
• Carefully consider intersections and what drivers are accustomed to.
• Carefully consider prioritization of other modes, such as bus. As discussed above, one 143 Elizabeth MacDonald, “Building a Boulevard.”
144 Elizabeth MacDonald, “Building a Boulevard,” 9.
145 John King, “An Urban Success Story.”
of the keys in any traffi c reduction scheme is to ensure the availability of other feasible if not attractive options. Maintaining or improving bus speeds is thus an important consideration.
• Carefully consider lane widths and design speed, particularly for local access lanes if they are to take on a mixed-mode character.
• Consider whether local traffi c being entirely separate is a prudent option.
• Consider future development: McGrath/O’Brien has a wider right of way, but the concept of keeping the new roadbed as narrow as possible will enable a maximum amount of development to orient itself along the roadway.
• Think creatively about parking requirements: a decrease in the minimum required parking, or placing a low upper limit on allowed parking, may decrease developer/owner costs, allow denser development, and encourage non-vehicular access.
• Plan for gentrifi cation and ensure adequate and creative affordable housing plans.
8.2: Precedent #2: Cyprus Freeway / Mandela Parkway, Oakland, CA
Across the bay, the creation of the Mandela Parkway is a similarly impressive
accomplishment, though, for one reason or another, not as well known. The Parkway
replaces the Cyprus Freeway, another double-decked viaduct that collapsed during the 1989 Loma Prieta Earthquake. The caveat at Mandela Parkway is that a new freeway was built, the I-880, in a new confi guration along the waterfront to replace the demolished Cyprus Freeway. However, its planning and construction took over 10 years, during which time the traffi c network adjusted, the neighborhood evolved, and the community took the time to demand a redesign they could use.
Mandela Parkway is much longer than the fi ve-block Octavia Boulevard – it is about a mile and a half in length and a full city block wide. The project extends from 8th Street to 32nd Street and involves improvements on both sides of the Mandela Parkway alignment and as well as the median, which varies in width from 65 feet to 110 feet. The project is roughly 18 blocks long with approximately 14 acres of landscaping.146
The Parkway was originally a surface road paralleling the enormous eight lane, double-decked Cyprus Freeway viaduct. More than 160,000 vehicles used this regional artery, the northern end of I-880, every day. The dramatic and deadly collapse of the viaduct on October 17, 1989 suddenly forced the closure of this major link. It also presented an opportunity to dramatically rethink this neighborhood and the infrastructural
146 Caltrans, “Mandela Parkway Improvement Project,” Accessed February 2011, http://www.dot.ca.gov/dist4/
Mandela/mandela.htm.
burdens it had borne since the 1960s and prior. As an industrial, lower-income, minority neighborhood, West Oakland typifi ed the type of district often targeted for infrastructure construction. The neighborhood was identifi ed as decrepit and ripe for urban renewal in the late 1950s, in spite of the strong community spirit there.147 The destruction and construction completely altered the face of the neighborhood in exchange for better regional connectivity:
“The construction of three major interstate highways and the Bay Area Rapid Transit (BART) complete the destruction of West Oakland in the 1960s.
Connecting the suburbs to downtown San Francisco the new transportation arteries sent San Francisco real estate prices soaring and provided suburban commuters access to good jobs. But their construction leveled large parts of West Oakland, isolating neighborhoods from one another and cordoning others off behind a mass of concrete. Construction of the BART line
destroyed a vital black commercial district of small stores and restaurants, jazz clubs, and barber shops…the new systems employed few and, even as a transportation system, bypassed West Oakland’s densest neighborhoods.”148
Given this legacy, the residents of West Oakland were eager to construct a transformational amenity to replace the Cypress Freeway. Similar to Octavia, the boulevard required years and much community activism to come into being. Community and business leaders placed great importance on the project: not only was it an attempt to mend a scar long imposed on the community, but it was also the chance to attempt to create a civic center for
Given this legacy, the residents of West Oakland were eager to construct a transformational amenity to replace the Cypress Freeway. Similar to Octavia, the boulevard required years and much community activism to come into being. Community and business leaders placed great importance on the project: not only was it an attempt to mend a scar long imposed on the community, but it was also the chance to attempt to create a civic center for